Class 8 Science - Chapter Sound NCERT Solutions | In the following statements, tick T agai
In the following statements, tick T against those which are true, and F against those which are false:
(a) Sound cannot travel in vacuum. (T/F)
(b) The number of oscillations per second of a vibrating object is called its time period. (T/F)
(c) If the amplitude of vibration is large, sound is feeble. (T/F)
(d) For human ears, the audible range is 20 Hz to 20,000 Hz. (T/F)
(e) The lower the frequency of vibration, the higher is the pitch. (T/F)
(f) Unwanted or unpleasant sound is termed as music. (T/F)
(g) Noise pollution may cause partial hearing impairment. (T/F)
(a) True
This statement is true because sound cannot travel in vacuum. Sound is produced by vibrations. If there, air is not present then sound cannot be produced.
(b) False
This statement is false because the number of oscillations per second of a vibrating object is called its frequency.
(c) False
This statement is false if the amplitude of vibration is large, then the sound will be sharp and having a high pitch.
(d) True
This statement is true because the range of hearing a sound is 20 Hz to 20000 Hz. Above 20,000 Hz the sound is not audible and harmful for ears.
(e) False
This statement is false because as higher is the frequency, the pitch of the sound is high.
(f) False
This statement is false because the unwanted and unpleasant sound is termed as noise pollution whereas the pleasant sound is known as music.
(g) True
This statement is true because noise pollution is harmful to the ears and it may cause partial hearing impairment. The unwanted and unpleasant sound is known as noise pollution.
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Fill in the blanks with suitable words.
(a) Time taken by an object to complete one oscillation is called ................... .
(b) Loudness is determined by the .........................of vibration.
(c) The unit of frequency is..........................
(d) Unwanted sound is called ......................... .
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